Identify a special character in an array of chars

I am writing a client/server application. I have a Message class with several String fields. I have written the following method to return a char[] of these fields:

public char[] toArrayOfChar()
{
    String str = "";
    char[] charr;
    str += from;
    str += "\r\n";
    str += to;
    str += "\r\n";
    str += header;
    str += "\r\n";
    str += body;
    str += "\r\n";
    str += header;
    str += "\r\n";
    charr = str.toCharArray();

    return charr;
}

Now I want to separate each field and convert it to a String after I have sent it from client to server. How do I identify the carriage return and line feed characters a开发者_如何学运维t the end of each field?

For your actual question, good answers have been given, but about your code style:

It's horribly inefficient to use multiple String += calls. Here's a much more efficient version.

First define a constant for cr + lf:

private static final String CRLF = "\r\n";

Now use StringBuilder to build the String, like this:

public char[] toArrayOfChar()
{
    return new StringBuilder()
        .append(from).append(CRLF)
        .append(to).append(CRLF)
        .append(header).append(CRLF)
        .append(body).append(CRLF)
        .append(header).append(CRLF)
        .toString()
        .toCharArray();
}

This is both easier to read and more efficient (your version has to create a new String instance for every += call).

Also, maybe you should just write this code (minus the .toCharArray() line) in your object's toString() method and do this.toString().toCharArray() to get the char[]. It's always a good practice to utilize standard mechanisms, this is what the toString() method is for, create a String representation of the object.

I suggest you look into the PrintWriter and BufferedReader classes, as suggested in the official trail: Reading from and Writing to Sockets.

Using these classes you can simply send your strings using

out.println(from);
out.println(to);
out.println(header);
out.println(body);

and read using

String from   = bufferedReader.readLine();
String to     = bufferedReader.readLine();
String header = bufferedReader.readLine();
String body   = bufferedReader.readLine();